Apple Video Cards & Monitors

Apple NTSC is not compatible with any other RGB, TTL or Analog types.
It is used with Apple IIc and some others. It uses the DB15 2-row
connector, just like the MAC series, but is electronically different.

Apple Native refers to on-board (not removable) video ports.

Apple frequency is 75 hz, VGA is 60 hz (vertical refresh rate).

The original MAC II (without any modifying letters) is an 8-bit
video card and is NOT compatible with any VGA, RGB or others.
It can only be connected to an Apple or clone monitor.
It has composite sync only, not separate Horz and Vert sync.

The newer MAC IIs such as MAC IIsi, MAC IIci, etc. are all 16-bit,
the same as the LC, Quadra, Centris, etc. The Quadra AV is switch
selectable to use either 75 hz or 60 hz frequency.

As of 12-31-93, to my knowledge and according to John Amoratta at
MicroMatch, all Apple monitors support COMP SYNC only, not separate
Horz and Vert Sync, and therefore cannot be used with VGA or RGB cards.
Also, Apple monitors run at 75 Hz frequency, VGA is 60 Hz.

Due to frequency difference, the strapping in the pinout must
sometimes be artificially set to the next lower resolution type in
order to work.

In other words, an 1152 x 870 VGA monitor at 60 hz will only be
capable of 1024 x 768 at Apple's 75 hz. This is not true in all
cases, but is generally true when the resolution is pushed to the
maximum capability of the monitor. Thus, a monitor capable of
1152 x 870 that is receiving a 640 x 480 signal will not care which
frequency is used.

The monitor's maximum limit is a PRODUCT of both the resolution
rating and the signal frequency. To achieve maximum resolution,
a lower frequency must be used. The lower the frequency, the higher
the potential resolution.

The pinouts for Apple MAC computers to VGA type monitors are in
the following files: